Final answer:
The red stripe on the barber's pole represents blood, a holdover from when barbers also conducted bloodletting and other medical procedures.
Step-by-step explanation:
The red stripe on the barber's pole represents blood. This symbolism dates back to a time when barbers performed not only hair cutting and shaving but also medical procedures like bloodletting. The barber's pole itself is a type of sign used by barbers to signify the place or shop where they perform their craft. The pole may have a helical stripe (often red and white in many countries) that is reminiscent of a staff around which a bandage was wrapped, symbolizing the bloodstained bandages used during and after the procedure. As barbers evolved into a separate profession focused solely on cutting hair and shaving, the iconic barber's pole remained as a symbolic legacy of the trade's history.